This invention relates to rotary pumps for feeding hot pitch, asphalt and like viscous solidifiable material, and more particularly to a rotary pump having an improved packing gland whereby hot pitch or asphalt which leaks along a driving shaft is solidified and reduced into powder before falling on a floor.
Rotary pumps such as internal gear pumps are widely used to feed hot asphalt or pitch. With rotary pumps, the pumping fluid is usually allowed to leak little by little through a clearance around the circumference of a driving shaft to provide lubrication between the driving shaft and the packing which surrounds the drive shaft, thereby ensuring a prolonged life of service. For instance, the internal gear pump has two eccentric gears accommodated within a housing. one of the gears is rotated by a driving shaft which is carried in an end plate of the housing. A packing casing is also provided on the end plate around the driving shaft to encase a packing which controls the leakage of pumping fluid through the circumferencial clearance of the driving shaft. The packing is held in position in the casing by a packing gland which is fit in and securely bolted to the packing casing.
When the conventional rotary pump is used to feed hot asphalt or pitch at 300-500.degree. C, difficulty is encountered in that the leaking pitch drips from the outer end of the packing gland onto a floor and grows into a large lump or lumps of solidified pitch, requiring additional labor for removal at certain time intervals, particularly in a continuous operation.
It is an object of the present invention to provide a rotary pump for hot asphalt, pitch and like viscous solidifiable material, which will eliminate the above-mentioned difficulty.
It is a more particular object of the present invention to provide a rotary pump for hot asphalt, pitch or like viscous solidifiable material, which is provided with grinding means for powdering the solidified material for easy removal.
It is another object of the invention to provide a rotary pump of the class mentioned above, which is provided with a cylindrical extension at the outer end of the packing gland in which the leaking material is solidified and reduced into powder before falling on a floor.
It is still another object of the invention to provide simple grinding means which can be easily adapted to conventional rotary pumps to be used for feeding hot asphalt, pitch or like viscous solidifiable material.